1. Field of the Invention
The present invention relates to a printing apparatus, a correction pattern, and a computer system.
2. Description of the Related Art
In recent years, a type of color printer that ejects several colors of ink from its head has gained wide popularity as an output apparatus for computers. Some such inkjet color printers have a function for performing so-called “bidirectional printing” in order to increase the printing speed.
Also, inkjet printers were only capable of reproducing each pixel according to binary values of on and off; however, in recent years, multivalue printers that are capable of reproducing a single pixel with multiple values, such as three or more values, have also been proposed. Multivalue pixels can be formed by ejecting ink droplets of the same color for a single pixel in a plurality of sizes, for example.
When performing bidirectional printing using a multivalue printer, with which a plurality of ink droplets are ejected for a single pixel, the image quality may be deteriorated due to differences in the printing characteristics in the forward pass and in the return pass. For example, when the positions where ink droplets of various sizes land in the main-scanning direction are different during the forward pass and the return pass, the image quality is deteriorated as a result.